I rarely let anyone use my PC because I’m afraid he will mess it up, but it seems Microsoft has been thinking at me and came with a solution. The PC Safeguard doesn’t let anyone mess your PC settings, because after the user logs off, the configurations are reset back to normal. Of course it will not restore the configurations changed by you, but only the ones done by other users you define.

To use PC Safeguard, go to Control Panel -> User Accounts and create a new account, then select “Set Up Pc Safeguard” and switch it on. Then you can stay relaxed when others use your computer, because you won’t find anything changed, including configurations, downloaded software, installed programs.